THE EXTRACTION OF JUICE BY MILLS. 



The chief factors in determiniDg the economic limit are 7 : 



1 . The type of crushing plant, whether two or three mills. 



2. The degree of admixture of the added water. 



3. The proportion of sugar extracted for market on the total brought 

 into the juice as the result of maceration. 



4. The thermal efficiency of the factory as a whole, including the boiler 

 plant, the method of evaporation, triple or quadruple effect, and the general 

 internal economy. 



5. The money value of the marketed sugar. 



6. The cost of coal or other fuel. 



7. The fuel value of the extra sugar extracted. 



8. The expenses of making, handling, transporting, &c., the extra sugar 

 made. 



9. The sugar content of the cane. 



10. The cost of the increased evaporating and other plant to deal with 

 the larger quantities of juice. 



An attempt follows to unite all these factors into one expression. 



Following on what has already been written, it is simply a matter of 

 calculation to find what amount of extra sugar is extracted as the result of 

 added water ; for this purpose the following data have been adopted : ] 



Canes (a). 13'69 per cent, sugar, 12*00 per cent, fibre, crushed in the 

 first mill to 30 per cent, fibre give 60 per cent, of juice, containing 16-15 per 

 cent, sugar ; crushed further in a second mill to 45 per cent, fibre give 

 13-33 per cent, of juice, containing 15-34 per cent, sugar. The residual 

 megass 26*67 per cent, on the canes contains 14*67 juice per cent, on cane, 

 the juice containing 13*40 per cent, sugar. 



Canes (i). 10-26 per cent, sugar, 12-00 per cent, fibre crushed as in the 

 above case, give first mill juice 12-07 per cent, sugar, second mill juice 

 11*46 per cent, sugar, residual juice in megass 10-20 per cent, sugar. 



To the megass from canes of the above composition let water be added 

 after the second crushing, and let the megass be again crushed to the same 

 fibre content. The amount of diluted juice obtained is evidently the same as 

 the water added, and the amount of sugar brought into the juice can be easily 

 calculated when the coefficient of admixture is known. In calculating the 

 tables below a coefficient] of -85 has been adopted, and of the sugar thus 

 brought into the juice -85 is estimated as capable of extraction as marketable 

 sugar. The value of this sugar is taken as 9 per ton or 1-90 cents per pound. 

 The expenses of obtaining this sugar are ascertained on the following basis : 

 The composition of the expressed diluted juice is calculated allowing a purity 

 of 80 ; the tons of water necessary to be evaporated to concentrate this to 50 

 Brix, and then to masse cuite at 95 Brix, are calculated. Coal is taken 

 as worth 2 at the furnace mouth, and to give for use in the factory per lb. 

 burnt 8 Ibs. steam, each 1 lb. capable of evaporating 3 Ibs. in the triple and 



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